This is an application for a K08 award for Dr. Pandora Wander, a general internist and cardiovascular disease epidemiologist at the University of Washington, who aims to establish herself as an independent investigator in clinical diabetes research. The focus of the five-year project is epigenetics, an important emerging domain in translational diabetes research, for its promise as a source of both predictive biomarkers and potential interventions. Funds would support Dr. Wander in the attainment of three goals: (1) developing understanding of epigenetic mechanisms of hyperglycemia and insulin resistance (H&IR) in the general population and in high-risk sub-groups; (2) learning advanced methods appropriate for epigenetic studies and data analyses; and (3) completing a translational epigenetic research project integrating lab-based, clinical, and population-level investigations. She has established a mentorship team and advisory committee comprising internists, epidemiologists, a lab medicine physician, and a biostatistician with strong track records of research and mentoring. Hyperglycemia and insulin resistance (H&IR) cause substantial morbidity and mortality. Excess visceral adipose tissue (VAT) is a strong risk factor for development of H&IR. The mechanisms by which accumulation of VAT leads to insulin resistance remain obscure, however, and therefore therapies targeting this link have been limited. Current methods to detect early changes in glucose metabolism are expensive and time-consuming. Novel circulating biomarkers that coincide with these changes could provide information about diabetes pathogenesis and facilitate early detection. MicroRNAs are post-transcriptional regulators of gene expression that participate in cellular functions important to glucose metabolism including inflammation, adipogenesis, and angiogenesis. They can be measured in tissues and in the circulation. The hypothesis for this application is that circulating levels of miRNAs (including let-7, miR-103/-107, miR-126, miR-144, and miR-181) that are differentially expressed in VAT and upregulate pro-inflammatory targets, are prospectively related to the development of H&IR. This hypothesis will be tested using a study with three arms: a cross-sectional study in a healthy American cohort, and two case-control studies in cohorts at high diabetes risk (Asian Americans and pregnant women). The primary aims are: To test (1) whether levels of circulating inflammatory VAT-related miRNAs are associated with greater insulin resistance in a healthy American population; (2) baseline plasma levels of inflammatory VAT miRNAs are prospectively associated with a higher incidence of glucose intolerance at 10-year follow-up in an Asian-American population; and (3) plasma levels of inflammatory VAT in early pregnancy are associated with a higher incidence of gestational diabetes. Follow-up in silico/in vivo experiments will characterize identified miRNAs and facilitate translation of findings. Identifying miRNAs related to incident H&IR will advance understanding of the pathogenesis of diabetes, improve early detection, and facilitate new interventions aimed at prevention.